The present remote sensing techniques in planetary atmospheres use well known transitions ranging from the microwave to the UV with large successes and due to Rayleigh scattering in dense atmospheres. Few environmental sensors are designed to operate below 280 nm. In the Mars atmosphere, however radiation down to 200 nm can certainly reach the surface and can be used as a source for gaseous composition observations Also, penetration of solar UV-B and C in planetary atmospheres is an important element in determining the sterile character of the surfaces and has to be simulated using atmospheric models demanding a knowledge of UV radiative transfer. An other use of UV radiation could be the in-situ spectrometry of gases, ices and minerals using specialized lamps allowing thus nighttime and subterranean observations The status of the UV spectroscopic data base is discussed. Existing UV sensors on approved missions to Mars will be described with emphasis on their astrobiological implications.